High voltage antistatic apparatus



March 7,1967 I H. w. SMITH ETAL 3,303,344

HIGH VOLTAGE ANTISTATIC APPARATUS Filed March 4, 1965 2 Sheets-Sheet 1 g V A 1/ Y INVE/VIOAS M2040 W gM/n/ 650265 fie Koexas lirraeA/exr.

H. w. SMITH ETAL HIGH VOLTAGE ANTISTATIC APPARATUS I March 7, 1967 2 Sheets-Sheet 2 Filed March 4, 1965 H mg A/VENTO/QSZ 15/2 2040 WI 5114/ 714 @5026; 4. {502x05 I 0 I I 0 0 0 0 H 0 47-70mm vs.

United States Patent 3,308,344 HIGH VOLTAGE ANTHSTATIC APPARATUS Harold W. Smith, San Marine, and George A. Korkos, Los Angeles, Calif, assignors to Ener-Jet Corporation, Phoenix, Ariz., a corporation of California Filed Mar. 4, 1965, Ser. No. 437,028 17 fiiaims. (Cl. 317--2) This invention relates generally to antistatic treatment of electrically charged objects, and more particularly concerns improvements in ion generation and dispensing apparatus for altering the static charge on work surfaces.

In certain processing operations there has long been a need for removing static charge from work surfaces. Typical processing apparatus where static charge builds up on fiber or paper surfaces includes the following: feeder aprons in cotton gin stands, cotton gin lint cleaners, slides and overhead feed distributors, rollers in cotton roller gins, textile mill card webs, silver and tow, and looms for processing either natural or synthetic fibers, paper handling equipment such as printing presses and rug fiber manufacturing, process, handling and transporting equipment and hair treating apparatus. In addition, moving particles and material, and even people walking over rugs and other surfaces often generate static charge, the intensity of which can be increased by weather conditions, including temperature and humidity. Such charge build-up often results in balling, sticking and jamming of the fiber, paper or hair being processed, inhibiting the efiiciency of the processing operation. Past efforts to solve this problem have not proved to be entirely satisfactory, and do not offer the unusual features and advantages of the present invention, insofar as we are aware.

It is a major object of the present invention to overcome the charge build-up problems discussed above through the provision of unusually effective, simple and compact ion generation and dispensing apparatus for altering, as for example neutralizing or changing, the static charge on work surfaces. Basically, the apparatus comprises electrically conductive means such as a conductive needle assembly having multiple pointed tips, and means to supply high voltage of positive or negative polarity to the needle assembly, the needle tips being spaced apart and directed to generate ions acting with electrical repulsion effect in the space about the needles to establish an ion stream moving away from the tips for application to the work. Typically, each assembly may include multiple needles directed in mutually diverging relation and forming a generally conical cluster. Also, the high voltage supply circuit may be varied to produce the reaction desired, so that pro-existing static charge on work may be increased, neutralized or changed by the ion stream flowing from the apparatus. The spacing between adjacent tips may be made less than inch tohelp secure the forward flow of the ion stream by repulsion effect. If desired, gas such as air may be supplied to flow forwardly along the assembly and over the needle tips for positively displacing the ion stream, the gas flow being directed by passage through a perforated dielectric front plate through which the needle assembly may project.

Other unusual objects and advantages of the invention include the provision of means to sense the static charge proximate the work and to control the high voltage supply to the needle clusters in response to such static charge sensing; the provision of multiple electrically conductive needle assemblies and parallel connected isolation resistors through which high voltage is supplied to the different needle clusters; and the provision of a simple yet highly effective DC. voltage supply circuit that inton descending on the slide.

33%,344 Patented Mar. 7, 1967 cludes an auto-transformer having a voltage controller and connected to the input of a voltage step-up transformer, and a voltage multiplying rectifier and capacitor network electrically connected between the step-up transformer and the isolation resistors; and the provision of an unusual subdivided material cleaning process using positive and negative charge.

These and other objects and advantages of the invention, as well as the details of illustrative embodiments, will be more fully understood from the following detailed description of the drawings in which:

FIG. V1 is an overall perspective view showing the combination of the ion generating and dispensing apparatus with a cotton gin;

FIG. 2 is a vertical cross section taken through one of the heads of the ion generating and dispensing apparatus;

FIG. 3 is a frontal view taken on line 3-3 of FIG. 2; FIG. 4 is a circuit diagram showing the elements to supply high voltage DC. to the needle assemblies;

FIG. 5 is a fragmentary section taken through the front plate of a modified head;

FIG. 6 illustrates a fragmentary section taken through another modified head; and

FIG. 7 illustrates the manner in which several heads may be used to clean particulate or fibrous material.

Referring first to FIG. 1, a cotton gin is indicated generally at 10 as having a cotton feed 11, a slide 12 along which cotton fiber 13 descends, and a lower unit 14 containing saws or other apparatus to clean and process the cotton. Cotton fiber 13 tends to develop static charge and to ball upon the slide 12, preventing uniform delivery and distribution thereof to the lower unit 14, so that the latter functions less efficiently than is possible in the absence of the static charge build-up on the cotton. To solve this problem, the ion generating and dispensing apparatus shown at 15 is centrally mounted as by bail support bracket 16 directly facing the slide 12 so as to jet a high concentration of ions, as in an ionized gas stream, in a forward direction and over a wide angle discharge pattern 17 for continuously treating the cot- Such treatment alters the static charge build-up on the cotton fibers, as for eX- ample by neutralizing the static charge, to stop balling, bunching or non-uniform delivery of the cotton to the lower unit. As a result a more continuous, increased flow and a cleaner, more high grade cotton product is produced -by the gin, enhancing its economic value.

Extending the description to FIGS. 24, the apparatus 15 is illustrated to include multiple heads 18 spaced along and mounted to the bracket 16, as for example by fasteners 19 projecting below the chambers 20. Carried at each head is what may be characterized as electrically conductive means having multiple pointed tips, and typically constructed in the form of a needle assembly indicated generally at 21. The needle assembly includes multiple needles 22 directed in mutually diverging relation and forming a generally conical cluster. For example, there are five needles in the assembly 21, one of which seen at 22a constitutes a forward projection of the carrier needle 22b. The other four needles 220 are clustered about central needle 22a and diverge at acute angles with respect to one another and the central needle 22a. When high, voltage, of the same polarity is supplied to the needles and their forward tips, a corona effect takes place to generate ions acting with electrical repulsion effect in the space between and about the needles to establish a negatively charged ion stream moving forwardly and away from the tips in the direction of arrow for application to the work, as for example the positively charged cotton in FIG. 1. In this manner, when apply- 3 ing about 10,000 volts to the points of the needles, concentrations of about to 10 ions per cubic centimeter of the same polarity can be achieved within a yard forwardly of the needle tips.

The invention also contemplates the provision of means to supply gas to flow over the tips for positively displacing the generated ion stream. For the purpose, the gas supply means may include the needle mounting chamber 20 forming a part of the head 18, and comprised of dielectric material such as a suitable plastic. The chamber has a gas inlet 25 to which line 26 delivers gas such as air from a suitable blower 27.

Chamber 20 has a perforated dielectric front plate 28 through which the needle assembly projects, and more specifically FIG. 2 shows the carrier needle 22b projecting through the forwardly diverging orifice or perforation 29. High voltage is supplied to the needle 22b by the lead 30 connected to the chamber 20 at 31. As a result, gas or air entering the chamber interior sweeps over the needle 22b, through the orifice 29, and then over the needles 22a and 22c and their tips to positively displace the ion stream forwardly and further toward the work. FIG. 5 shows a modified chamber front plate 33 divergently orificed at locations 34 to pass air flowing about and along needles 22c, which project through said orifices, the tips being spaced forwardly of the plate.

Referring now to FIG. 4, it illustrates one form of means to supply high voltage of the same polarity to multiple needle assemblies indicated at 21, each assembly being of the same type as discussed above. The illustrated high voltage supply means, which has been found to be unusually effective, compact and otherwise advantageous, includes a circuit to supply up to and in excess of 10,000 volts DC. at the needle tips, the latter in each cluster being spaced apart by less than inch.

The circuit indicated generally at 36 includes an autotransformer 37 providing a coil 38 across which 60 cycle input voltage, as for example 117 volts, may be supplied via plug 39, leads 40 and 41, switch 42 and fuse 43. The auto-transformer includes an output voltage controller, as for example manually controlled tap 44 slidable along coil 38 to vary the voltage applied to the primary coil 45 of transformer 46 between 0 and 117 volts. The turns ratio of the step-up transformer 46 is typically such as to develop several thousand volts (as for example 4,0'00 volts R.M.S.) at the terminals of the transformer secondary coil 47. v 1

As seen in FIG. 4, a voltage multiplying rectifier and capacitor network 48 is electrically connected between the output side of step-up transformer 46 and a series of parallel connected isolation resistors 49 through which high voltage is supplied to the needle tips in the bank of needle assemblies 21. Typically, about 12,000 volts DC.

may be supplied in this manner, for creating negative ions,

and the network 48 functions, as a voltage tripler. Network 48 includes a capacitor 50 connected in series with output lead 51, and oppositely poled rectifiers 52 and 53 connected between leads 51 and 54 via capacitor 55, as shown. Rectifiers 52 and 53 connect with lead 51 at opposite sides of capacitor 50, and network 48 also includes another rectifier 55 in series with that lead. Other circuit elements include the current limiting safety resistor 56, and filter capacitor 57. Isolation resistors 49 function as current limiters and also to isolate the needle assemblies one from another, so that if one assembly starts to generate negative ions before another assembly, the current or voltage available to the other needle assemblies will not be undesirably and substantially reduced. I Finally, FIG. 4 indicates the provision of means to sense the static charge proximate the work and to control the high voltage supply in response thereto, typically in such feedback sense as to reduce the supply voltage as the unwanted static charge at the work decreases below a predetermined level, and to increase the supply voltage as the static charge at the work increases above a predetermined level. One unusually effective means for performing this function is shown to include a static charge pick-up element 60 and a static charge integrator 61 ex-posable to the work proximity 62 and located to effect charging of the pick-up 60 in proportion to the voltage at the integrator. For example, the integrator may comprise, in essence, a curved plate capacitor having grounded plate 63 insulated from a sensing plate 64 exposed to the work area as well as to the plate 65 at the pick up. As static charge integrates or collects on integrator plate 64, the voltage thereon builds up in accordance with the equation V=Q/ C (1) where V voltage at the plate '64 Q=charge on plate 64 C :eifective capacitance of 61.

As a result, a proportional voltage builds up at plate 65 of pick up 60 exposed to plate 64. The voltage induced at the pick up is supplied via lead 66 to control 67 operating to govern the voltage at the primary of the step-up transformer. For this purpose, the control 67 may operate an actuator 68 for the tap 44 at the autotransformer.

A neon pilot or indicator bulb 70 may be connected, as shown, across the primary coil of the step-up transformer.

Positive ions, instead of negative ions may be produced at the tips of the needle assemblies, and for this purpose the polarities of the rectifiers 52, 53 and 55 may be reversed. For example, switch arms 90, 91 and 92 may be provided for movement to engage contacts 93, 94 and in series with reversed polarity rectifiers 52a, 53a and 55a, placing the latter in the circuit and simultaneously disconnecting rectifiers 52, 53 and 55 therefrom.

FIG. 6 illustrates another modified form of head designated at 72, and including a chamber 73 formed of plastic material. The electrically charged carrier needle 74 projects axially through a dielectric front plate 75 having divergent perforations 76 to direct air or gas streams 79 to flow toward the charged multiple needle tips 77 forwardly of the plate. The latter are housed within the flaring forward port-ion 73a of the chamber 73, which has an outer sheath of conductive material such as aluminum that is grounded for safety purposes.

In FIG. 7, a processing duct is seen at through which subdivided, dry, chargeable solid material is adapted to pass, as indicated at arrows 101. Apparatus is provided to subject the material to alternate positive and negative charge treatment as the material passes within the duct. Typically, ions of positive and negative polarity are generated and dispersed into different regions of the treatment zone 102 of the duct, positive charge region being indicated at 103 and negative charge region at 104. Such treatment tends to loosen contaminating particles from the material (as for example dirt or other foreign particles from cotton fibers) as by an electrical shaking effect, whereby the material may be at least partially cleaned in the zone 102. Charge separated particles may then be removed from the zone 102, as for example through a neutral or grounded screen 106 and removal ports 107 at one side of the ducts, typically the lower side to take advantage of gravity. Positive and negative high voltage sources are seen at 108 and 109 as having connection through switches 110 and 111 with the ion generatordispensers 112 and 113 spaced along the side of the duct 100 opposite the screen 106. Generator-dispensers 11 2 and 113 may have the construction as discussed above in FIGS. 1-4, or FIG. 5, or FIG. 6. This electrical cleaning process avoids the problem of mechanical shaking, which tends to break up fibers that are most desirably kept long for greater value and utility.

We claim:

1. Ion generation and dispensing apparatus for altering the static charge of work, comprising electrically conductive means having multiple pointed tips, and means to supply high voltage of the same polarity to said first means, the tips including a first tip and other tips spaced about said first tip with all tips directed generally forwardly to generate ions acting with electrical repulsion effect in said space to establish an ion stream moving forwardly and away from the tips for application to said work.

2. Ion generation and dispensing apparatus for altering the static charge of work, comprising an electrically conductive needle assembly having multiple pointed tips, and means to supply high voltage of the same polarity to said assembly, the tips including a generally centrally located first tip and other tips substantially equally spaced about said first tip with all tips directed generally forwardly to generate ions acting with electrical repulsion effect in said space to establish an ion stream moving forwardly and away from the tips for application to said work.

3. Apparatus as defined in calim 2 in which said assembly includes multiple needles including an inner needle terminating at said first tip, and outer needles terminating at said other tips and directed in mutually diverging relation and forming a generally conical cluster, the assembly including dielectric means extending in directly rearwardly spaced relation to all the tips and proximate said needles.

4. Apparatus as defined in claim 3 in which said means to supply high voltage provides in excess of 10,000 volts DC. at said tips, the spacing between adjacent tips being less than inch to produce ion concentrations of about to 10 ions per cubic centimeter up to a yard forwardly of the tips.

5. Apparatus as defined in claim 2 including means to supply gas to flow forwardly along said assembly and over said tips for displacing said ion stream.

6. Apparatus as defined in claim 5 in which said gas supply means includes a chamber having a perforated dielectric front plate through which said needle assembly projects.

7. Apparatus as defined in claim 6 in which said needle assembly includes multiple needles directed forwardly in mutually diverging relation forwardly of said plate, the assembly including a support needle projecting through a perforation in said plate.

8. Apparatus as defined in claim 6 in which said needle assembly includes multiple needles directed forwardly in mutually diverging relation and through perforations in said plate.

9. Apparatus as defined in claim 1 including means to sense the static charge proximate the work and to control said high voltage supply in response thereto.

10. Apparatus as defined in claim 9 in which said means to sense the static charge includes a static charge pick-up element and a static charge integrator exposable to the work proximity and located to effect charging of the pickup in proportion to the voltage at the integrator.

11. Apparatus as defined in claim 2 in which said high voltage supply means includes a circuit to supply in excess of 10,000 volts DC. at said needle tips, the circuit including an auto-transformer having a voltage controller, a voltage step-up transformer having its primary coil electrically connected with the output of said auto-transformer, and a voltage multiplying rectifier and capacitor network electrically connected between the step-up transformer secondary coil and said needle assembly.

12. Ion generation and dispensing apparatus for altering the static charge of work, comprising multiple electrically conductive needle assemblies each of which has multiple pointed tips, and means to supply high voltage of the same polarity to said assemblies with the assemblies electrically connected in parallel, the tips of each assembly including a first tip and other tips spaced circularly about said first tip with all tips directed generally forwardly to generate ions acting with electrical repulsion effect in said space to establish an ion stream moving forwardly and away from the tips for application to the work, said means including parallel connected isolation resistors respectively connected in series with said assemblies and through which high voltage is supplied to said tips.

13. Apparatus as defined in claim 12 in which said high voltage supply means includes a circuit to supply in excess of 10,000 volts DC. at said needle tips, the circuit including an auto-transformer having a voltage controller, a voltage step-up transformer having its primary coil electrically connected with the output of said auto-transformer, and a voltage multiplying rectifier and capacitor network electrically connected between the step-up transformer secondary coil and said isolation resistors.

14. Apparatus as defined in claim 12 in which each assembly includes at least three needles directed in mutually diverging relation and forming a generally conical cluster.

15. Apparatus as defined in claim 12 including means to change the polarity of high voltage application to said tips between positive and negative.

16. Apparatus as defined in claim 6 in which the chamber has a dielectric tubular portion directly surrounding said tips and forming a forwardly flaring front opening to pass the ion stream and said gas, and including an electrically grounded outer sheath for said chamber.

17. Ion generation and dispensing apparatus for altering the static charge of work, comprising electrically conductive means having multiple pointed tips, means including an auto-transformer to supply high voltage of the same polarity to said first means, the tips being spaced apart and directed generally forwardly to generate ions acting with electrical repulsion effect in said space to establish an ion stream moving forwardly and away from the tips for application to said work, and means to sense the static charge proximate the work and to control the voltage output of said auto-transformer in response thereto, said last named means including capacitance having a first plate exposed to the work area to collect charge and a second plate subject to charging in proportion to charge collection on the first plate, an actuator operable to control the auto-transformer, and means to control operation of the actuator in response to changed charging of the second plate.

References Cited by the Examiner UNITED STATES PATENTS 1,604,406 10/ 1926 Gayle 317-2 X 1,968,861 8/ 1934 Strang 19-9-8 2,043,217 6/1936 Yaglou 317-4 X 2,740,184 4/ 1956 Thomas. 2,765,975 10/1956 Lindenblad 317-2 X 3,048,766 8/1962 Panzer 321-15 FOREIGN PATENTS 126,963 11/1958 U.S.S.R.

MILTON O. HIRSHFIELD, Primary Examiner. LEE T. HIX, Examiner.

J. A. SILVERMAN, Assistant Examiner, 

1. ION GENERATION AND DISPENSING APPARATUS FOR ALTERING THE STATIC CHARGE OF WORK, COMPRISING ELECTRICALLY CONDUCTIVE MEANS HAVING MULTIPLE POINTED TIPS, AND MEANS TO SUPPLY HIGH VOLTAGE OF THE SAME POLARITY TO SAID FIRST MEANS, THE TIPS INCLUDING A FIRST TIP AND OTHER TIPS SPACED ABOUT SAID FIRST TIP WITH ALL TIPS DIRECTED GENERALLY FORWARDLY TO GENERATE IONS ACTING WITH ELECTRICAL REPULSION EFFECT IN SAID SPACE TO ESTABLISH AN ION STREAM MOVING FORWARDLY AND AWAY FROM THE TIPS FOR APPLICATION TO SAID WORK. 